There about 1300 IV shell companies, companies that don’t invent, have no employees, and are all about suing. In a word, patent trolls. Here’s how the name came about according to Peter Detkin, the guy who coined the term:

Oh, the story of a troll kind of fits â€˜cause the whole Billy Goats Gruff thing, itâ€™s someone lying under a bridge they didnâ€™t build, demanding payment from anyone who passed.